The objectives of the proposed research are to : (1) determine the primary structure of human plasma apo low density lipoprotein (LDL) responsible for cholesterol transport, (2) determine the primary structure of human erythrocyte membrane protein responsible for glucose translocation, and (3) determine the primary structure of glycogen synthase, the enzyme that catalyzes transfer of a glycosyl residue from UPD-D-glucose to the terminal glucose residue at the nonreducing end of an amylose chain to produce glycogen. The mass spectrometric protein sequencing techniques of K. Biemann and H. R. Morris will be employed in these studies. In addition we intend to develop new methodology for determining the amino acid sequences of proteins by mass spectrometry. We propose to: (1) use gas phase isotope exchange ion molecule reactions to facilitate interpretation of spectra obtained on multicomponent mixtures of derivatized polypeptides, (2) develop derivatization techniques which allow us to use the 100-500 fold increase in sensitivity afforded by electron capture negative ion CIMS and to obtain sequence information on low nmole or picomole samples, (3) to explore the utility of collision induced decomposition mass spectrometry (CID) for the direct analysis of polypeptide mixtures on our newly constructed triple stage quadrupole mass spectrometer, (4) develop combined liquid chromatography-laser desorption CIMS for on line sequence analysis of understanding polypeptide mixtures, and (5) to study the utility of various CI-reagent gases for directing fragmentation of derivatized polypeptides to yield specific structural information.